循环赛的分组列表组合

Question

编辑：我的问题不是有人标记的重复问题。另一个问题不正确，甚至不起作用。

我尝试了几种方法来对 itertools.combinations 的结果进行分组，但无法得出正确的输出。需要在游戏中创建匹配项。每支球队每天都需要比赛，但只有一次。球队需要在接下来的几天打不同的球队，直到每个人都打完。

teams = [team 1, team 2, team 3, team 4]
print list(itertools.combinations(teams, 2))

结果：

[(team 1, team 2), (team 1, team 3), (team 1, team 4), (team 2, team 3), (team 2, team 4), (team 3, team 4)]

但我需要的是将它们分组，不要有任何重复的列表项。示例：

[
    [(team 1,team 2), (team 3,team 4)], #day 1
    [(team 1,team 3), (team 2,team 4)], #day 2
    [(team 1,team 4), (team 2,team 3)]  #day 3
]

如有任何提示，我将不胜感激，我觉得可能有一个简单的单行代码就可以完成这项工作。

Answer 1

基于链接问题中的 Scheduling_algorithm 使用 collections.deque 的实现：

from collections import deque
from itertools import islice

def fixtures(teams):
    if len(teams) % 2:
        teams.append("Bye")

    ln = len(teams) // 2
    dq1, dq2 = deque(islice(teams, None, ln)), deque(islice(teams, ln, None))
    for _ in range(len(teams)-1):
        yield zip(dq1, dq2) # list(zip.. python3
        #  pop off first deque's left element to 
        # "fix one of the competitors in the first column"
        start = dq1.popleft() 
        # rotate the others clockwise one position
        # by swapping elements 
        dq1.appendleft(dq2.popleft())
        dq2.append(dq1.pop())
        # reattach first competitor
        dq1.appendleft(start)

输出：

In [37]: teams = ["team1", "team2", "team3", "team4"]

In [38]: list(fixtures(teams))
Out[38]: 
[[('team1', 'team3'), ('team2', 'team4')],
 [('team1', 'team4'), ('team3', 'team2')],
 [('team1', 'team2'), ('team4', 'team3')]]

In [39]: teams = ["team1", "team2", "team3", "team4","team5"]

In [40]: list(fixtures(teams))
Out[40]: 
[[('team1', 'team4'), ('team2', 'team5'), ('team3', 'Bye')],
 [('team1', 'team5'), ('team4', 'Bye'), ('team2', 'team3')],
 [('team1', 'Bye'), ('team5', 'team3'), ('team4', 'team2')],
 [('team1', 'team3'), ('Bye', 'team2'), ('team5', 'team4')],
 [('team1', 'team2'), ('team3', 'team4'), ('Bye', 'team5')]]

循环赛的分组列表组合

Grouping list combinations for round-robin tournament

python

combinations

list

itertools